A Preamp for ARS Filarmonia ?

The Adcom is not a passive preamp as it has gain.See the following quote from the Stereophile test.

Other than glue logic and the transistors used to drive the relays, the 12 active devices—four gain blocks, each with three devices—are HEXFETs from International Rectifier. The output stage is intended to function as a pure voltage source, making the GFP-750 relatively immune to cable differences or low amplifier impedances. As we've come to expect from Adcom, the preamp sports a honkin' big toroidal transformer, with multiple secondary windings for each channel. A large heatsink on the left-hand side carries the power supply regulator chips.

Passive preamps have no active stages at all, just input selectors and volume controls. A very good passive is the Creek OBH 22. The Adcom has a passive phono equalization I believe but has, as you see, gain stages.

Maybe something like this then?
http://www.goldpt.com/sa4.html

This device looks good Traudio
I have Dual input/output BAM with both RCA and XLR
I try to use both inputs but the loudness between the inputs is so much difference and it sound too muddy regardless of output be RCA or XLR. Unplug either one will bring back the clarity and sweetness. Not sure because the "conversion" from RCA to XLR and vice versa ?
Thanks
Thuan

I ordered mine with a break, (not sure what else you'd call it) in the circuit. Basically another pair of RCA's so the pre-out goes to the bam and the BAM out comes back in that extra pair of RCA's. This allows for exactly what you're after. All sources plugged into Filarmonia, BAM in signal path, etc....

the only downside I guess is that if a non-BAM user wanted to use this amp they'd need to use a short interconnect to bridge the pre-out and new set of rca's.

To look at it I can't imagine it would cost much at all to do. It just looks like a pair of RCA's and an extra wire soldered in. But I'm not tech savvy that way so who knows.

Sounds great and works like a charm.

Best of luck.